Accurate processing on a work in a process stage requires the work to be prevented from vibrating.
The work is divided into a processing region and a non-processing region along a circumferential direction, and in many cases, moves together with a main shaft in a state where a holding part for vibration stop is in pressure contact with an already processed region of the work.
As shown in FIG. 5, in the pressure contact state of the holding part of a prior art, a pressure contact region is too small. Thus, it cannot be avoided to make a partial region of the holding part come into pressure contact.
On the other hands, the pressure contact state causes a problem that the pressure contact region of the holding part intrudes into a region recessed by the processing, in the other words, in a recess, and even if the work is to be rotated along a columnar center axis for the next processing, such rotation is hindered due to the intrusion.
However, in the prior art, no particular countermeasure has been taken for the problem caused by the pressure contact region of the holding part intruding into the recesses that has been formed by the processing.
For reference, Patent Document 1 describes, regarding a camshaft work to be ground, a processing region and vibration stop for the work, nevertheless has no particular description on the relationship between the processing region and the vibration stop.
Patent Document 2 describes both processing on a work and a vibration stop device, but does not describe the problem arising when the pressure contact region comes into contact with the region that has already been processed.